The nutrition of medical and surgical patients has become a matter of clinical importance within the last decade. Since initial reports of parenteral nutrition of an infant in the mid-1960's nutritional support has been of inestimable value in reducing the mortality of serious diseases and the morbidity related to certain types of operations. Following the development of techniques for parenteral alimentation, especially intravenous feeding, interest has increased in enteral alimentation using the gastrointestinal tract. The use of specially defined chemical or elemental diets containing a known quantity of protein, amino acids, carbohydrates, and fat with low osmolality is as effective as intravenous nutritional support when the patient's gastrointestinal tract is intact and functioning. Although not suitable for all patients, enteral alimentation is safer, easier, and better accepted by the patient. In addition, enteral alimentation is more economical than parenteral alimentation. For example, the cost to administer 3,000 calories intravenously is over 10 times greater than the cost of supplying the same caloric support through enteral alimentation. Further, by using an intact gastrointestinal tract for alimentation, the major problems of sepsis and metabolic derangement which relate to intravenous alimentation are largely obviated. Another major advantage is that adequate nutritional support is greatly simplified.
Historically, polyvinyl chloride nasogastric tubes have been used to infuse special diets. These tubes have proven unacceptable for several reasons. One problem has been that gastric acid tends to migrate along the tube at the esophagogastric junction causing furrows and erosion of the mucosa in the distal esophagus. This can result in stenosis or hemorrhage. Larger tubes are also tolerated very poorly by the patient because of continuing nasopharyngeal irritation and patient discomfort. Recently, the use of small silicone rubber feeding tubes has proven advantageous in the administration of elemental diets. However, due to the uniformity of size and suppleness of the silicone rubber tubes, at times it has proven virtually impossible to pass these tubes through the nasopharynx into the esophagus and stomache. Various devices including sylets and the back of a wooden Q tip have been used to insert the tube, but are not satisfactory. At times, an empty capsule has been used to join the silicone rubber feeding tube to a larger nasogastric tube so that it can be passed through the nose and into the stomache. The tip of the tube has also been provided with holes through which the diet emerges and these holes act to reduce the strength of the tube and make insertion difficult. At the present time, the difficulty of introducing small silicone rubber and similar feeding tubes is the chief barrier to their use despite their medicinal advantages and improved patient care.
Various devices besides a simple tube have been proposed in the prior art to perform enteral alimentation. For example, in U.S. Pat. No. 1,736,182 (Wilkins), a stomache feeding tube having a mercury weighted end portion with holes adjacent to the weighted end is disclosed. Another prior art feeding tube is disclosed in U.S. Pat. No. 3,155,097 (Barron). This patent discloses a feeding tube having a looped lower end with holes therein for even dispersing of the liquid. The device disclosed in this patent also includes a gravity balloon weight which is partially filled with mercury. The use of a heat sealed polyvinyl chloride mercury filled capsule affixed to the distal end of a standard 42 inch polyvinyl chloride No. 8 F feeding tube with several additional side holes cut in the distal end is disclosed in an article by Boddie and Hoffmeister entitled "Continuous PumpTube Enteric Hyperalimentation" in Surgery, Genecology and Obstetrics, August 1976, Volume 143 at Page 273.
Other devices in the prior art have also been disclosed for delivering or removing a fluid from a patient's body. For example, in U.S. Pat. No. 4,068,664 (Sharp et al), a surgical suction wand assembly is disclosed having a tipped portion with holes therein which can be fitted to a smaller diameter tube. In U.S. Pat. No. 3,741,217 (Ciarico), a catheter is disclosed which has multiple inlet passages leading to a single main passageway. The use of slits or slots in place of holes at the end of the catheter have also been disclosed in U.S. Pat. Nos. 4,168,699 (Hauser), 4,129,129 (Amrine), and 3,885,561 (Cami). In order to indicate the position of a catheter, a radiopaque stripe on the catheter has been disclosed in U.S. Pat. No. 3,938,529 (Gibbons).
Although the prior art has disclosed feeding tubes and like devices, the prior art has not disclosed a feeding tube which is both comfortable to the patient, safe, and easy to insert.